Field of the Invention
This invention relates in general to rail structures and in particular to a new and useful bogie for rail vehicles which has a low seated loading ramp.
The invention relates particularly to a bogie for rail vehicles with a deep-seated loading ramp, comprising at least two wheel sets with a small axle base and a bogie frame or car comprising side walls and transoms between two axles. The sets of wheels are fastened in the bogie frame by means of the axle bearings, and the bogie is connected to the car frame merely by means of a load carrying leaf spring and a suspension ring arranged laterally and lengthwise. Catches limit the movement of the bogie relative to the rail vehicle.
Bogies for rail vehicles with a loading ramp located below the buffer level are known. Usually sets of wheels with a small diameter are used, the bogie bolster or the connection of the lateral cheeks of the bogies are cranked downward in the transverse center of the bogie to receive a swivel ring. In this arrangement the large axle base due to the cranking of the bogie bolster or the connection of the lateral cheeks of the bogies is a drawback.
German patent DE-PS 23 02 550 discloses two-axle bogies or four-wheel bogie, in which the bogie frame carries a horn plate or half-axle guard or guide which is vertically open and whose inner shape is that of a rectangle at each of the transverse ends in its longitudinal center. Herein a straight and level horn plate which is fastened to the bogie frame protrudes into the horn plate guide. In the known embodiment of a two-axle or four-wheel bogie, the bogie is guided on the vehicle like a single axle. Longitudinal play and lateral play as well as the horizontal swing of the bogie are limited by the play in the horn plate guide. The small axle base achieved by this means comes as close as possible to the movement pattern of a single axle. The missing swivel ring or live ring allows for a very low headway. Furthermore, the base or bed plate for the carrying leaf spring is located in front of the axle bearings in transverse directions with regard to the bogie to achieve the low headway.
In this embodiment it is disadvantageous that the carrying leaf spring is arranged directly on the lateral cheeks, which because it is limited upward by the freight hold of the vehicle and downward by the structure gauge merely allows for the use of very short suspension rings for the suspension of the carrying leaf spring. The short suspension rings, which represent the only direct connection between the bogie and the superstructure, result in very high righting moments and therefore result in stronger guiding forces during the taking of curves when the bogie rotates or swivels. A further disadvantage of this bogie is that the lateral play will not be adequate for the dynamics of vehicle movement due to the small spring base and taking into account the kinematic load limit gauge profile.